Laboratory Tests on Masonry Vaults with Backfill Strengthened at the Extrados

Abstract

This paper deals with the experimental behavior of two masonry vaults strengthened externally with a composite material. Thickness, internal span and rise of the vaults were 120 mm, 2000 mm and 730 mm, respectively. Masonry was made of solid clay bricks and lime mortar. An alkali-resistant coated glass fiber grid embedded in a cement-based matrix was used as strengthening material. The tensile strength of the glass grid as specified by its manufacturers was about 45kN/m. Both of the tested vaults were strengthened at their extrados. Expanded clay aggregate or lightweight concrete were used as a backfill. The vaults were tested under monotonic vertical loads applied at a quarter span. The main aim of the research presented here was to develop a strengthening method acceptable for vaults with frescoes, to determine the load-carrying capacity and to examine failure modes of the tested specimens. The results of the tests show that observed failure modes depend on the backfill configuration.